New Commuting Geek Seeks 6 Volt LED Solution
02-11-06, 04:28 PM
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So, today in Michigan it's snowing fairly quickly, and I test-ran my first commute; I plan to start commuting by bike on Monday in earnest.
I bought a Nitehawk Raptor - 10 W - and it seems to be pretty good in terms of light. I'm about halfway through the Geek thread, and I'm already thinking of replacing it with some sort of Luxeon LED M16 setup.
However, I was hoping to power it with only 6 volts. What's the easiest/best solution? My first thought (as a mere *mechanical* engineer) was that there would be a simple resistor in there (which slvoid seems to say is the case with some Cateye products) - and I could reduce the resistance, pop everything back together, and be off and running.
I should mention that I was hoping not to pay the $130 for a whole 3W LED system from Cygolite - and I don't even know if that system is 6V.
Should I disect a flashlight? Some other solution?
BTW, thanks to everyone for making the commuting forum such a success - the lightchart Excel spreadsheet, the beginning commuters, and the geek threads were invaluable.
I bought a Nitehawk Raptor - 10 W - and it seems to be pretty good in terms of light. I'm about halfway through the Geek thread, and I'm already thinking of replacing it with some sort of Luxeon LED M16 setup.
However, I was hoping to power it with only 6 volts. What's the easiest/best solution? My first thought (as a mere *mechanical* engineer) was that there would be a simple resistor in there (which slvoid seems to say is the case with some Cateye products) - and I could reduce the resistance, pop everything back together, and be off and running.
I should mention that I was hoping not to pay the $130 for a whole 3W LED system from Cygolite - and I don't even know if that system is 6V.
Should I disect a flashlight? Some other solution?
BTW, thanks to everyone for making the commuting forum such a success - the lightchart Excel spreadsheet, the beginning commuters, and the geek threads were invaluable.
02-12-06, 08:40 AM
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Paying $130 for a 3W LED system is really overkill. 3-watt Luxeon Stars cost less than $20 and have a Vf of like 3,4 volt (white). Can definitely be driven by 6V, even 4.5. Driving them is really easy, if you don't care about nuking away some power as heat. Just do a LED series resistor calculation like you would do with any other LED, but keep resistor heat margins and LED current margins generously large.
Want to be more effective? There's always buck-dump inductive drivers but it requires knowledge, some effort and a microcontroller.
https://www.microchip.com/stellent/id...pnote=en012124
if you need more help just let me know. I'm studying EE and pretty interested in LED applications
Want to be more effective? There's always buck-dump inductive drivers but it requires knowledge, some effort and a microcontroller.
https://www.microchip.com/stellent/id...pnote=en012124
if you need more help just let me know. I'm studying EE and pretty interested in LED applications
02-12-06, 06:09 PM
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Originally Posted by grapetonix
Paying $130 for a 3W LED system is really overkill.
Another question - I was hoping to power it with 5 Ni-Cd batteries - does anyone have the discharge rates curve for Ni-Cd batteries?
02-12-06, 08:36 PM
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Originally Posted by grapetonix
Paying $130 for a 3W LED system is really overkill. 3-watt Luxeon Stars cost less than $20 and have a Vf of like 3,4 volt (white). Can definitely be driven by 6V, even 4.5. Driving them is really easy, if you don't care about nuking away some power as heat. Just do a LED series resistor calculation like you would do with any other LED, but keep resistor heat margins and LED current margins generously large.
Want to be more effective? There's always buck-dump inductive drivers but it requires knowledge, some effort and a microcontroller.
https://www.microchip.com/stellent/id...pnote=en012124
if you need more help just let me know. I'm studying EE and pretty interested in LED applications
Want to be more effective? There's always buck-dump inductive drivers but it requires knowledge, some effort and a microcontroller.
https://www.microchip.com/stellent/id...pnote=en012124
if you need more help just let me know. I'm studying EE and pretty interested in LED applications
Perhaps some of the multi-LED arrays woudl give as much l;ight and be far more efficient. I bow to your wisdom.
